When you have a pest infestation, one of the telltale signs is the smell. For rats and mice it's a rank, ammonia stench that singes your nostril hair. For bedbugs it's a sickly sweet, yeasty odour, cloying and icky. How do I know? Because I've just inherited a house that comes with some unwanted residents thrown in for free.

I'd like to think that this problem doesn't affect anyone else, because I wouldn't wish it on my worst enemy, but I know that isn't true. According to a 2010 survey, the world is on the verge of an international "bedbug pandemic". Rentokil reported a 24% increase in UK bedbug jobs between January and June 2010 compared with the same period in 2009.

You'll probably realise you have bedbugs when you get bitten. They crawl along your skin, munching as they go and leaving a trail of bites. Conventional wisdom says you only get bitten at night, but I've been attacked in the daytime (mind you, the house had been empty for a while so the bugs were probably ravenous). Then you itch for a couple of days. Other signs include tiny spots of blood on your sheets and, if you look carefully, you might be able to see the bugs (or their newly hatched nymphs) yourself.

As for rats, you'll hear scrabbling noises in the walls or floors that make you want to rip off your ears, or you may see their poo. They leave dark, pellet-shaped droppings that can be up to 14mm in length. The bigger the poo, the bigger the rat, so avoid measuring them in case your worst fears of giant mutant rodents are confirmed. Gnawing marks, ripped food packets, and piles of shredded paper, fabric and plastic all indicate a rodent presence. We've found evidence in many of the rooms in our house, so don't think they're confined to places where food is kept.

Before you BURN THE HOUSE DOWN, though, it is possible to rid yourself of these nasty beasts.

In the first instance, it's good to stop the bedbugs biting. A colleague came up with an ingenious suggestion for this. He explained how, as a student, he'd moved his bed away from the wall and stuck double-sided sticky tape around the legs. Any critters climbing up to get him would be trapped on the glue in the night - flypaper for crawlers, if you will. You're buggered if your bed has drawers underneath, though.

Ultimately, you need to get in the experts. They will examine your house to see how bad the infestation is and then bring out the heavy guns if necessary. For bedbugs, this will either involve a new heat treatment, or you'll have to move all your furniture to the middle of the room and get it, and the walls, sprayed with insecticide. It could take up to four treatments depending on the situation, and four to six weeks for them to be successfully wiped out.

For rodents, again get in the experts. I spoke to my local council's environmental health department:

If you have rats underneath the floors ... there is a very high possibility that there is a drain fault in the property. It could be simply a missing rodding eye cap which may or may not be the result of a blockage. If rats are under a floor on a more than one-off basis then the drainage system should be first port of call, and no amount of blocking with wire wool/foam etc will make a jot of difference.

This was after I put forward a Sarah Beeny tip from Channel 4's
Help! My House is Falling Down, which advised stuffing wire wool into any rodent gaps and then filling with expandable foam. Kate Hamer, the UK technical manager at Rentokil, said that if the drains are not faulty then this may help:

Rats can get through holes approximately 10mm in diameter, so blocking up any gaps this size or larger is the key priority. For small ones, scrunched-up wire wool can be used to block them. The wire wool should be packed as tightly as possible, and the rats will not chew through it. Some people combine this with expanding foam, to improve the cosmetic appearance and prevent drafts. However, expandable foam alone will not stop rats - they will chew through it.

As well as eradicating the rodent underground transport system by repairing drains and blocking holes, it will be necessary to put down poison and/or traps. Again, the experts will be able to advise you on what's best, but if you have children or non-pest animals then a "rat killer box" is a safe, sealed unit.

Our visitors look set to stay until we save enough money to call in the council's pest control (likely to cost at least £350); they starve to death (the house is empty); or we persuade Sarah Beeny to bring her TV crew over and fix 'em for good.

If you have any tips for dealing with rodent or insect intruders, or if you just want to share your horror stories, please post your comments below.